1. SENSORY PERCEPTION Types of receptors, associated organs 1

2. Functions?  Convert energy into a change in membrane potential of sensory receptors  Four major functions:  Sensory transduction – convert stimulus energy into change in membrane potential  Amplification – strengthening stimulus energy  Transmission – carry stimulus to CNS  Integration – processing sensory information 2

3. Types of Sensory Receptors  Mechanoreceptors  Chemoreceptors  Electromagnetic receptors  Thermoreceptors  Pain receptors 3

4. Mechanoreceptors  Physical deformation (bending/stretching)  Pressure  Touch  Stretch  Motion  sound 4

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6. Mechanoreceptors in inner ear 6

7. Chemoreceptors  General: (total solute concentration)  Osmoreceptors in brain – stimulate thirst  Specific: (individual kinds of molecules)  Glucose, oxygen, carbon dioxide, amino acids 7

8. Taste 8

9. Smell 9

10. Electromagnetic receptors  Detect various forms of electromagnetic energy  Visible light: Photoreceptors (Eyes)  Electricity (Fish that detect prey that disturb electric currents)  Magnetism (Animals that migrate sense magnetic fields) 10

11. Thermoreceptors  Respond to heat, cold  Signal both surface and body core temperature  Much debate on where these are in humans… (encapsulated or naked?)  Communicate with hypothalamus (body’s thermostat) 11

12. Pain Receptors  A.k.a. nociceptors  Unencapsulated (naked) dendrites  Different groups respond to various stimuli:  Excess heat  Excess pressure  Chemicals released from damaged, inflamed tissues  Certain chemicals raise/lower threshold of pain receptors 12